Udeina petrosi, Plisko, 2004

Plisko, Jadwiga Danuta, 2004, Review of the balantine genus Udeina Michaelsen, 1910 with descriptions of six new species in South Africa (Oligochaeta: Acanthodrilidae, Acanthodrilinae), African Invertebrates 45 (1998), pp. 287-287 : 305-307

Udeina petrosi sp. n.

Figs 13–15

Etymology: Named after Mr Petros Ngwenya of Ezemvelo KZN Wildlife, who assisted in collecting the type material.

Type material: Holotype: clitellate NMSA /Olig.03371 KwaZulu­Natal: Highmoor State Forest (29º18'33"S: 29º35'54"E), grassland at the edge of marsh, in moist soil, 14 March 2001, JDP, A. J. Armstrong, P. Ngwenya . Paratypes: NMSA /Olig.03616, 7 clitellate ; NMSA /Olig.03617, 7 juvenile; all collected with holotype .

Description:

External features:

Body cylindrical, in life dorsally violet, ventrally yellowish­grey; alcohol­preserved dorsally violet, with stronger tint on preclitellar segments; ventrally yellowish­gray. Clitellate 90–128 mm long, 4 mm wide. Segment number: holotype 160; clitellate paratypes 158–166, aclitellate 117–161. Prostomium: tanylobous with evident sutures. Setae: widely paired; on postclitellar segments aa <bc; ab <cd. Dorsal pores: not observed. Nephridial pores: on holotype not observed; on two paratypes noted in b setal lines in intersegmental furrow 21/22, and in selected posterior furrows. Spermathecal pores: in intersegmental furrow 7/8, in front of b. Female pores: paired in 14, in front of b setae. Clitellum : saddle­shaped, on 13–1/n18; anterior border at intersegmental furrow 12/13, clitellar tissue on segment 13 slightly thinner than on 14–17; posterior border on 1/n18; lateral edges extend to rows of papillae in zigzag lines, bordering papillae located on 13–17. Prostatic pores: one pair in small round papillae encircling b setae, in segment 19. Seminal grooves ( Fig.13): paired, longitudinal slightly curved, between posterior part of 17 and prostatic pore of 19; in 18 noted small depression being male pore. Male pores: paired, small openings in 18, lateral to b setae; indicated by vas deferens entering body wall behind ab setae, posteriorly to 17. Papillae: paired, below b setae, parallel with ventral clitellar borders on segments 13–17; small swellings, oval, flat. It is not known if papillae of 17 support ectal prostatic ducts of the evidently reduced prostates of segment 17.

Internal characters:

Salivary glands: not extending beyond septum 4/5. Gizzard: well developed, in 5, muscular, cylindrical with anterior soft fold. Septa: 5/6–6/7 thin, 7/8–12/13 increasing in thickness, muscular, 13/14–15/16 thinner; some variations in thickness in dissected individuals were observed. Intestine: commences in 16. Lateral hearts: four pairs, thin vessels, last pair in 12. Nephridia: large elongated coiled loops without terminal vesicles, posterior smaller. Ovaries: large funnels attached to intersegmental furrow 13/14. Testes and spermiductal funnels: spermiductal funnels large, free, medially in segment 10, iridescent. Vasa deferentia : one pair; anteriorly covered by thick tissues of body wall, run backwards parallel to axis of the body to 15, where become evident as single, soft tube, extending to posterior part of 17, and entering into body wall. In majority of dissected paratypes, after passing vestigial parts of muscular ducts of the reduced prostatic gland of segment 17, run backwards and enter into body wall near intersegmental furrow 17/18. It is, however, not known if posterior part of vas deferens enters into well­marked externally small depression in intersegmental furrow 17/18, or extends into noticeable depression in 18 that might be male pore. Seminal vesicles: two pairs; in 9 and 11, differing in size; in 9 very small, laterally attached to 9/10; in 11 larger, connected at septum 10/11, composite sacs extending dorsally. In dissected paratypes some variations in size and shape were observed, which might be due to different states of individual maturity. Spermathecae ( Fig. 14): one pair in segment 8.Ampulla elongated, connected with duct above diverticulum. Duct moderately thick with ectal parts entering body wall in intersegmental furrow 7/8; short, not longer than 4 1 of the length of ampulla. Diverticulum attached at basal region of spermathecal duct, much smaller than ampulla, variable shapes and folds indicating two partially separated divisions. Prostates ( Fig. 15): one well­developed pair in 19, and one pair of small, vestigial prostatic ducts in 17; ectal openings in 17 not confirmed. Prostatic duct in segment 19 muscular, coiled or looped several times in the same segment, extending backwards into 20, evidently entering prostatic pore in segment 19. Prostatic gland much thicker than duct, multi­folded, looped, passing irregularly backwards and forwards through segments 18–23; septa are pierced, or only conically extended. The rudimentary ducts of segment 17 differ in size and states of development, being however similar to ectal parts of ducts in segment 19, in six dissected individuals. These vestiges can occur paired, or single, either at left or right side of the body, but occur only in segment 17. Penial setae: ab setae of segment 19 transferred into penial setae. Differ in size, being probably in different states of development. Penial setal retractor muscles: commence at septum 18/19.

Biological notes and distribution: This species was collected in moist grassland soil, at edge of muddy depression, in the foothills of Drakensberg escarpment.Associated with the microchaetid Proandricus bergvillensis Plisko 2000 , and other acanthodrilines of the genus Parachilota .

Discussion: A distinctive species, having in addition to the well­developed prostates in segment 19, the additional pair of vestigial parts of the prostatic ducts in 17. No developed prostatic glands in 17. These vestigial ducts may suggest reduction of the anterior pair of prostates, which are present in the species of the sister genus Parachilota . The spermathecal diverticulum is small, attached to the basal region of the spermathecal duct, with partially separated divisions, variable in size.